The present invention relates to a headlamp where control on a pattern of brightness-intensity distribution is performed mainly by a reflector, and in particular to a headlamp whose interior is made difficult to see to some extent without losing a high brightness feeling of inside metal and which has a high degree of freedom on an optical design and a method for manufacturing a reflector in the headlamp.
There have been known a headlamp which uses a flat lens. However, the headlamp uses the flat lens, and the inside (lamp chamber) of the headlamp can be seen clearly through the flat lens. The inside can be seen clearly, and it is necessary to finish the interior of the lamp chamber politely, and correspondingly the inside finishing is complicated.
Also, since the reflected light reflected and controlled by the reflector is allowed to pass through the flat lens as it is without controlling the reflected light, the degree of freedom on the optical system design is small.
An object of the present invention is to provide a headlamp whose inside is made difficult to see to some extent without losing a high brightness feeling of inside metal and whose degree of freedom is large on an optical system design and a method for manufacturing a reflector for the headlamp.
In order to achieve the above object, a first aspect of the invention provides a manufacturing method for a reflector of a headlamp. The method has the steps of setting up a first reflection surface of a reflector for a first brightness-intensity distribution pattern to be projected through a flat lens to conform to a target brightness-intensity distribution pattern; calculating a displacement between the target brightness-intensity distribution pattern and a second brightness-intensity distribution pattern, the second brightness-intensity distribution pattern being reflected by the first reflection surface and to be projected through a curved lens; and setting up a second reflection surface of the reflector for the displacement to become substantially a zero.
A second aspect of the invention provides a headlamp. The headlamp has a reflector having a second reflection surface for reflecting light rays from a light source; and a curved lens for projecting reflected light rays to outside therethrough. The second reflection surface is set up relative to a first reflection surface to conform a second brightness-intensity distribution to be projected through the curved lens to a target brightness-intensity distribution pattern. The first reflection surface is for conforming a first brightness-intensity distribution pattern to be projected through a flat lens to the target brightness-intensity distribution pattern.
Preferably, the curved lens has a concave surface.
Preferably, the curved lens has a convex surface.
Preferably, the curved lens has a concave surface and a convex surface. The second reflection surface of the reflector conforms a third brightness-intensity distribution pattern to pass through the concave surface and a fourth brightness-intensity distribution pattern to pass through the convex surface to a target brightness-intensity distribution pattern respectively.
As a result, since the headlamp of the present invention uses the concave lens (4) or the convex lens (5), when the inside of the headlamp is seen through the concave lens (4) or the convex lens (5), it becomes difficult to see the inside to some extent due to light refraction (refer to solid line arrows L24, L34, L25, L35 in FIG. 1) without losing a high brightness feeling of inside metal. Accordingly, it is unnecessary to perform the inside finishing of the headlamp so politely and correspondingly the inside finishing is made easy.
Also, since the reflected light (L24, L25) reflected and controlled by the reflector (6,7) is further refracted and controlled by the concave lens (4) and/or the convex lens (5) to be projected as projecting light (L34, L35) outside, the degree of freedom on optical system design is increased as compared with the case using the flat lens (3).
According to the method for manufacturing a reflector for a headlamp of the invention, the reflector (6, 7) for a headlamp whose inside is made difficult to see to some extent without losing a high brightness feeling of inside metal and whose degree of freedom is large on an optical system design can be manufactured. In addition, the reflector (6, 7) for the above-mentioned headlamp can be manufactured with a high accuracy, at a high speed and with a high degree of freedom by performing the provisionally setting step of the reflector (2), the displacement calculating step and the primarily setting step of the reflector (6, 7) according to a predetermined program in a computer.
In other words, the target brightness-intensity distribution pattern can be obtained by a reflection surface of the reflector (2) manufactured according to a general expression and parametric functions which have been changed on the basis of the general expression of the equation (1) and the parametric functions of the equation (2).